Spectrophotometric applications of digital signal processing

Abstract

Spectrophotometry is more and more often the method of choice not only in analysis of (bio)chemical substances, but also in the identification of physical properties of various objects and their classification. The applications of spectrophotometry include such diversified tasks as monitoring of optical telecommunications links, assessment of eating quality of food, forensic classification of papers, biometric identification of individuals, detection of insect infestation of seeds and classification of textiles. In all those applications, large numbers of data, generated by spectrophotometers, are processed by various digital means in order to extract measurement information. The main objective of this paper is to review the state-of-the-art methodology for digital signal processing (DSP) when applied to data provided by spectrophotometric transducers and spectrophotometers. First, a general methodology of DSP applications in spectrophotometry, based on DSP-oriented models of spectrophotometric data, is outlined. Then, the most important classes of DSP methods for processing spectrophotometric data—the methods for DSP-aided calibration of spectrophotometric instrumentation, the methods for the estimation of spectra on the basis of spectrophotometric data, the methods for the estimation of spectrum-related measurands on the basis of spectrophotometric data—are presented. Finally, the methods for preprocessing and postprocessing of spectrophotometric data are overviewed. Throughout the review, the applications of DSP are illustrated with numerous examples related to broadly understood spectrophotometry.

A Multi-Band Integrated Virtual Calibration-Inversion Method for Open Path FTIR Spectrometry

“…These two approaches to solve for the variables are termed the forward-model approach and inverse-model approach [21]. A forward model that transforms the gas concentrations into a spectrum can be built for open-path measurements.…”

Measurement Data Processing in Spectrophotometric Analysers of Food

“…This methodology may be generalised on the measurands containing some other quantities, provided the corresponding physical, chemical or purely numerical models of the sensitivity of the spectrum    x to those quantities are available. The contents of this and three following sections at many points refer to the author's review paper of 2006 [116], where many more algorithmic details may be found.…”

Filter-Based Miniature Spectrometers: Spectrum Reconstruction Using Adaptive Regularization

“…Tikhonov regularization has been successfully applied to many fields for robustly solving inverse problems of ill-posed conditions. This method has also 1530-437X/$26.00 © 2010 IEEE been presented for improving the resolution of spectrophotometric analyses in the past [8]- [10]. Low complexity and robust methods for selection of the regularization parameter have also received much research attention [11]- [13].…”